The present application applies to fluid transfer in radiation treatment equipment, and particularly to the transfer of compressed air and/or other fluids to the moving portions of such equipment. While it finds particular application to radiation treatment equipment for use in medicine, it also relates to other applications in which a fluid is supplied to a moving portion of a treatment device.
Radiation treatment, in general, is the use of ionizing radiation for the treatment of an object. In medicine, radiation treatment is commonly used in the treatment of cancer and other disease. To this end, it is generally desirable to apply a desired radiation dose or dose distribution to a tumor or other region to be treated, while minimizing the dose supplied to healthy tissues.
One type of radiation treatment apparatus is described in U.S. Pat. No. 5,442,675 by Swerdloff et al. More particularly, a linear accelerator, and collimator are mounted to a rotating gantry. As the gantry rotates about a patient, a pneumatic actuator is used to vary the collimator and thus modulate the shape of the radiation beam applied to the patient from each of a plurality of angles or projections about the patient.
Compressed gas for operating the actuator is supplied to the rotating gantry via an airtight rotating union having roughly the same circumference as the rotating gantry. Thus, as the rotating gantry rotates about the patient, compressed air supplied through the rotating union is used to operate the actuator and hence vary the shape of the radiation beam applied to the patient.
While such a configuration has proven effective in practical treatment systems, there remains room for improvement. For example, the rotating unions can be relatively difficult to manufacture, and their reliability can be deleteriously affected by factors such as mechanical wear.
Another consideration is the delivery of a coolant that serves to cool the linear accelerator. To this end, the rotating gantry has included a closed loop cooling system. Unfortunately, however, the coolant must be changed or flushed from time to time to, among other things, remove particulate matter that may accumulate during use. Since the cooling system is integrated within the rotating gantry, however, a service technician has to be engaged to disassemble the scanner, flush the fluid and then reassemble the scanner—a time consuming, labor intensive, and therefore expensive proposition.